An odd question that has plagued me for years.  Being that whales are
mostly slow-moving, defenseless marine meat popsicles, why is it that
sharks or other predators don't simply eat them.  They seem the
ocean-going equivalent of a Sizzler buffet for large predators, yet
they continue to lumber about.

---

Request for Question Clarification by tutuzdad-ga on 22 Sep 2005 07:29 PDT

Oh, but they do. Did you know that Cookie-Cutter sharks (Isistius
brasiliensis) DO feed on whales, often taking huge chunks of flesh
right out of the animal's belly, back and tailstock?

AUSTRALIAN MUSEUM ONLINE
http://www.amonline.net.au/fishes/fishfacts/fish/ibraspyg.htm
http://www.amonline.net.au/fishes/fishfacts/fish/ibrasil.htm

GOOGLE IMAGES - COOKIE-CUTTER SHARK
http://images.google.com/images?svnum=10&hl=en&lr=&safe=off&q=%22COOKIE+CUTTER+SHARK%22+

This animal is well suited to bite the passing smorgasboard because it
can extend it's mandibles out far enough to latch on whereas other
more larger species cannot.

Does this answer your question?

Regards;
tutuzdad-ga

Hello, benprofane-ga! 


You have posed an interesting question. For the most part, whales are
simply too large to form viable prey for the average shark! However,
there is evidence that sharks occasionally attack whales to supplement
their diet.

Here are some distinct references concerning shark predation on whales:

 
Concerning Killer Whales:

From "Longevity and Causes of Death."
http://www.seaworld.org/infobooks/KillerWhale/deathkw.html
 
"Killer whales are top predators in the sea. Healthy adults have no
natural predators, but sharks prey on older, younger, or ill killer
whales."


===


Concerning Grey Whales:

From "ALL ABOUT WHALES."
http://www.enchantedlearning.com/subjects/whales/species/Graywhale.shtml

"Killer whales (orcas), the large sharks, and humans are the gray
whales' only natural predators. Orcas hunt gray whales off the pacific
northwest coast near Oregon, USA. Skin parasites (including barnacles
and whale lice) attach themselves to the head area, back, and blowhole
area also."


===


Concerning Humpback Whales:

From "Humpback Whales in Maui." Island Marine Institute
http://www.whalewatchmaui.com/maui.html

"Humpback whales have very few natural predators. There are a few
species of sharks that will feed on the sick, the injured, and the
young. Their only other predator, besides humans, are orcas, the
killer whale."


===


Concerning Narwhals:

From "Odontoceti Questions." Ocean Link
http://oceanlink.island.net/ask/odontoceti.html

"Predators of Narwhals include killer whales, walruses, polar bears
and sharks. However, these whales have also been traditionally hunted
by the Inuit for its valuable tusk and its thick skin."


====



Sleeper sharks with whale meat in their stomachs:

From "Sleeper Sharks: Awake and Hungry Sleeper sharks Not Culprits in
Sea Lion Declines," By Amy Carroll. Alaska Wildlife News
http://www.wildlifenews.alaska.gov/index.cfm?adfg=wildlife_news.view_article&articles_id=146&issue_id=26

"Most of the stomach contents were easily identified, and included
intact rockfish, walleye pollock and pink salmon, as well as cleanly
sliced larger fish including Pacific cod, chinook salmon, Pacific
halibut and chunks of marine mammals such as harbor seals and whales."


===


See the following question and answer on the MadSci Network:

"Do sharks attack carniverous, toothed, whales?"
http://www.madsci.org/posts/archives/may2001/990547816.Gb.q.html


===


I hope this helps to answer your question.


Sincerely,

umiat


Search strategy

natural predators of whales
shark predation on whales
Do sharks attack whales?
shark attacks on whales

---

Clarification of Answer by umiat-ga on 22 Sep 2005 09:32 PDT

Hello again, benprofane!

I hope the following references will provide some additional insight.


Concerning the comment below -

"I think your missing the heart of the question. It seems like a large
whale should be an EASY meal for a group of sharks..."

Perhaps the following article on killer whales (which are as ruthless
as sharks!) may shed some light on why large whales have a defense
against groups of hungry sharks:

From "Orcas and Sharks."
http://whale.wheelock.edu/archives/ask02/0278.html

"Orcas often hunt in packs, much like wolves. A pack will surround
their prey so that it canšt swim away, and then they take bites of it
until they kill it or until they are full. If they attack another
whale, they choose the weakest whale they find and attack its lips,
tongue, and belly."

** "However, the large whales have a defense. They have huge, powerful
tails, and can hit their attackers very hard. One person reported
seeing a killer whale thrown 30 feet away from its prey!"


==


I'm not sure that the ability to dive to greater depths, as suggested
in the comments, is the primary reason that whales are immune to more
frequent shark attacks. The following article mentions the diving
nature of great white sharks when they want to feed on whale
carcasses:

From "Evidence of Shark Predation and Scavenging on fishes equipped
with pop-up satellite archival tags." David W. Kersteller.
http://66.102.7.104/search?q=cache:kwUjzRluuJIJ:www.earthscape.org/r2/ES15617/v102n4p.pdf+shark+predation+on+whales&hl=en

"The diving behavior recorded by the three tags also corroborates
ingestion of the tags by sharks. Carey et al.(1982) reported that a
tagged white shark off Long Island, New York, made frequent dives to
the bottom during a 3.5-day acoustic tracking period. White sharks are
known to dive to depth while scavenging whale carcasses (Dudley et
al., 2000; Carey et al., 1982)."

==

Obtaining the proper angle for a good "bite" from a live whale, as
well as recognition of a "proper shape" may be another issue:

From "Shark Attack!" PBS Airdate: August 5, 1997
http://www.pbs.org/wgbh/nova/transcripts/2316shar.html
 
"Being warm-blooded also helps the shark to digest blubber, a very
rich source of energy. And no prey offers more blubber than a whale.
The great whales, like these humpbacks, may have once been important
to the shark's diet. Now, these whales are scarce, and to find a
carcass washed up on a beach is a rare treat for a foraging shark. If
there is one to be found, the shark's acute sense of smell will detect
it, even from miles away. This humpback whale will provide a huge
meal, hundreds of pounds of blubber. The challenge for the shark is to
find the proper angle to take a bite out of the massive carcass. A
meal like this can sustain a great white for over a month. But
scavenging whales is not a reliable source of food. A large predator
must have easy access to living prey, as the great white shark has at
the Farallons. In these rough waters where seals abound, Scot Anderson
has devised a way to get a whole new view of a shark attack. He
attaches a video camera to a board. Research shows that this
particular shape will provoke great whites. Scot and Peter Pyle motor
out to a place they know is teaming with sharks and float the board in
the water. Remarkably, no animal bait is needed to attract the sharks.
They are drawn simply by the shape of the board, oblong and roughly
six feet in length, the shape of a seal, a sea lion, or a floating
surfer. Sometimes, the sharks merely investigate the board and swim
by. But at other times, they stalk and attack. Following the initial
strike, the sharks may hover momentarily, but they rarely return for a
second bite. They know a good thing when they taste it, and this isn't
it. The fierceness of this attack startles even the most unflappable
scientist."

===

Finally - there is also evidence that sharks prefer "high-energy" pery:

From "White Shark.
http://www.flmnh.ufl.edu/fish/Gallery/Descript/Whiteshark/whiteshark.html


"Some evidence suggests that white sharks decide a prey's palatability
while it is lodged in the shark's mouth. Researchers also believe that
white sharks may prefer animals rich in energy, such as marine
mammals, in favor of less fatty, energy-poor prey. This is supported
by some observations of aggregations of white sharks selectively
feeding on the blubber but not the muscle layers of mysticete whales.
This behavior seems based upon a size-hierarchy, where large sharks
dominate in the feeding."

==

I hope this helps!

Ample information and good links answered my question sufficiently.

According to this site

http://www.blakeschool.org/academics/lower/mediaResources/0304whaleResearch/0304whaleResearch13.html

Question:	How does the blue whale behave when it is attacked? What are
its defenses?
Answer:	The blue whale uses its size, diving abilities, and speed to
avoid ocean predators. Unfortunately, the greatest predators are
people which they have no defense against.

and this one:

http://whale.wheelock.edu/archives/ask97/0358.html

Sharks may also prey on whales (as may killer whales), with groups often 
mobbing a lone animal.  Again, the whale's main defense would be to try to
outrun its aggressors. Dolphins have been frequently documented successfully
driving sharks away with head butts and bites, but for baleen whales this is
obviously not an option.

I think your missing the heart of the question. It seems like a large
whale should be an EASY meal for a group of sharks. Just swim up, take
a bite, repeat as desired. Yet whales aren't extinct, and they aren't
prolific reproducers. What keeps large whales from dissapearing faster
then ice cream cake at a birthday party?

Possible answers might be, Whales can get away by diving to depths
that sharks can't reach. Or... a shark's mouth really isn't capable of
biting into the side of a whale any more then a person could bite into
the side of a watermelon. Or.. Whales have secret ninjitsu skills...
or whatever...

In my opinion the question deserves a little more attention.

While the information posted does partially answer my question, I have
to agree with shockandawe in that the heart of the question remanins. 
His first paragraph nicely sums up the center of my confusion.

The further clarification by tutzadad answered my question
sufficiently.  Thank you for your help

Whales aren't swimming shark buffets for the same reason elephants
aren't walking lion buffets.  They're big, powerful, built like tanks,
and could easily injure or kill their attackers.

--->Whales aren't swimming shark buffets for the same reason elephants
aren't walking lion buffets.  They're big, powerful, built like tanks,
and could easily injure or kill their attackers.

How, being that they are move so much slower than their would-be attackers?

Ummm, may I join the fun...

Until we can interview intelligently some shark species, here are some
of the reasons why large whales are not eaten alive by sharks:

1)Most of the sharks see them big whales as factories of smaller fish.
Sharks eat smaller fish. So if sharks should attack and eat the
"golden geese" and so decimate the factories of sharks' food, them
sharks will starve to death after a while. Them sharks are no fool.
(?,shark...goose?). [Seeing these Big Mama's and Papa's eat only krill
and planktons, but no small fish of the varieties that sharks eat
everyday, sharks know that that their forefathers'
belief re tanker whales--passed on the succeeding sharks--is
well-founded. Yamato whales don't eat their offsprings. Aircraft
carrier whales are not lions, sharks know.] (?, whale...lion?).
(tanker/Yamato/aircraft carrier...?)

2)Most sharks are figure-conscious. They hate getting chubby or out of
shape. Sharks are streamlined. They have the best-looking figure in
the aquatic world (except for the eyes-holders of the hammerheads
species). They eat too much fat, they lose this figure. They'd be
porpoise-looking. Dugong. Walrus. No way! Don't eat them mountain
whales. Them are fat factories too. Eeeck. (?, mountain whales? not
island-whales?)

3)Most sharks are show-offs. Or, maybe, have inferiority complex. To
showw off to the land creatures, them sharks try to preserve them
volcano whales to show them landlubbers. "You think your elephants are
huge? Microscopic! Try comparing them tou our Big Mama's and Papa's!
[During the time of the dinosaurs, them sharks couldn't even whimper
re this boisterousness.)

4.) {The group-of-sharks-simultaneosly-attacking/devouring a fish is
for show only. If there are cameras around, especially television
cameras or video recorders, them sharks outdo each other to show-off
their ferocity. They (sharks) have reputations to protect. But when
nobody is around or looking or recording, them sharks toe the line so
that only one shark at a time is on the fish-food. Some species even
assign only one shark to do the honor of slicing the fish-food and
then giving the rest of the sharks a piece of the food.}

5.) If there are a few shark species that do attack/eat live
continent-whales, them sharks are exceptions to the rule. Them sharks
just dutifully perform the role given them. If on the land there are
exceptions to the ruile, so do them sharks.

Well, that settles that.

>>How, being that they are move so much slower than their would-be attackers?

Imagine it, you are the biggest living thing on the planet, you would
need to be pretty powerful just to move yourself.  Like a humpback
whale that is capable of launching its entire 50 ft long, 35 ton body
(http://en.wikipedia.org/wiki/Humpback_Whale), out of the water when
it breeches.  That is explosive power.  A single tail or flipper fluke
could easily injure a comparatively puny, cartilaginous shark.  Even
the largest predatory shark the great white (which itself hunts seals
not whales) is small compared to that at 20 ft and 2 tons
(http://en.wikipedia.org/wiki/Great_White_Shark). 35 tons vs 2 tons. 
There's no comparison. In the wild, a serious injury equals death from
not being able to get food, so the sharks aren't going to risk
attacking a full-grown whale.  Of course there are many kinds and
sizes of whales, but I am assuming from your original question that
you are talking about the large, baleen, blimp looking whales you
might assume are defenseless.